The invention relates in general to protective helmets and to a fastening means for a protective helmet by means of a chin strap which can be adjusted in length and which is connected to the shell of the helmet by a holding or fastening device.
A similar device has been shown, e.g. in the German OS No. 2 156 338, as an essentially conventional chin strap which is attached to strong leather segments arranged at the sides of the helmet with one snap fastener on each side. The chin strap is adjustable in length and serves to secure the helmet on the head of the wearer.
A disadvantage of this known fastening device and method is that the fit of the protective helmet cannot be guaranteed, especially under the influence of external force, and that at least a sliding of the helmet on the head is possible.